Flea bites are uncomfortable for your pet, causing irritation and itchiness. Many dogs are allergic to flea bites, explains the former director of veterinary services at the Society for the Prevention of Cruelty to Animals (Hong Kong). Many dogs and cats are allergic to the flea's saliva, which contains foreign proteins.

The parasites, which average about 1.5mm to 3mm in length, can also jump on to humans, transmitting worms or more serious diseases.

"Fleas on their own can be very uncomfortable - dogs or cats can scratch themselves silly," Stanley says. "Fleas can suck enough blood to make a cat anaemic." They can also transmit feline infectious anaemia disease, which may make the cat lose its appetite and appear jaundiced.

As many felines in Hong Kong are indoor cats, you would think they are safe from these tiny blood-suckers. Surprisingly, this isn't the case. Stanley says: "Cats can still have many, many fleas. Maybe they are brought in by their owner. We aren't sure how it happens, but you do see cases [of house-bound cats with fleas]."

If you have been using powders, sprays or collars to stave off a flea infestation, the vet recommends adding or switching treatments.

He says: "The only really useful prevention and/or treatment for fleas are spot-on treatments." The treatment is a liquid pesticide, which should be applied on the back of the animal's neck since it's an area where the animal can't lick it off. The pesticide then spreads right across a pet's skin, making any parasite that consumes the animal's blood likely to die.

Stanley adds that treatment should be applied once a month. Some brands also kill eggs and prevent them from hatching in the environment. When buying a spot-on product, Stanley suggests looking for newer versions that do not contain pyrethrin as it can be toxic. "Pyrethrin products are not as safe."

Stanley says one pregnant flea can lay a quarter of a million eggs over the summer months. Keeping fleas under control is key to having a happy, healthy pet.

"Hoovering is also a good idea," Stanley adds.

Ticks may appear to go hand in hand with fleas, but they are part of the arachnids family, which mean they are closer to a spider than to a flea. They can survive in near freezing temperatures, while fleas like warmer climates.

"A tick's bite does not tend to be itchy like a flea bite, but the place where a tick bites can become infected, and possibly fatal," Stanley says.

Ticks also transmit serious diseases, the most common being tick fever, which is prevalent in Hong Kong throughout the year.

The vet says tick fever is more a range of diseases than one specific illness. Some of the principal signs of tick fever are anaemia and red blood cells breaking down, and problems with blood-clotting.

"Often, you will see blood in the urine, bruises on the mucous membrane or your dog will look pale and weak," he says. "You can also get vomiting and nose bleeds."

Spot-on products also kill ticks, but they don't kill ticks quick enough to kill tick fever, Stanley says.

If you live in green areas, the vet recommends using a tick collar in addition to spot-on products.

The tick collar contains amitraz, an active ingredient that can kill and detach ticks. However, amitraz is toxic to some breeds of dogs, including the chihuahua.

"You can't be too careful with ticks. Some are only a couple of millimetres in length, but others are the size of a thumbnail," Stanley says.

"They can hang on and gorge themselves [on blood] until they drop off."

As with most health problems, the vet says prevention is far easier - and more effective - than the cure.